The subject matter disclosed herein relates to generators and repair of the same and, in particular, to an apparatus that restricts movement of a rotor (or “field generator”) during extraction of the rotor, e.g., from a gas turbine generator.
Generators include a stator and a rotor that rotates relative to the stator to generate electricity. Technicians often need to extract the rotor from the stator to perform repair and maintenance on the generator. In conventional practice, this task requires overhead cranes and rigging in combination with certain implements (e.g., field support shoes and core skid pans) to guide and support the rotor during extraction from the generator. The configuration of the rigging, however, is not typically standardized, but rather the construction of the generator and the experience and know-how of the technicians that are to complete the repairs and maintenance ultimately determine the way the rigging secures to the rotor.
The rigging often engages the rotor at points that are radially outside of the centerline of the rotor. This engagement directs the pulling forces, which extract the rotor from the stator, off-center from the centerline of the rotor. The resulting offset may cause the rotor to become unstable during extraction and, in some cases, prone to movement (e.g., rolling). Such movement can shift the weight of the rotor off of the field support shoes that are meant to prevent contact between the rotor and the stator or other components of the generator. In some cases, the resulting moment of inertia can cause inadvertent contact between the rotor and the stator, which can lead to extensive damage as well as substantial repair costs and machine downtime.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.